Computing sight



1950 H. BROWN 2,534,225

COMPUTING sma'r Filed 001;. 17, 1945 r 5 sheets-Sheet 1 H. BROWN COMPUTING SIGHT Dec. 19, 1950 3 Sheets-Sheet 2 "Filed Oct. 17, 1945 3mm LED H BREIWN,

W MMMM 61W Dec. 19, 1950 L. H. BROWN 2,534,225

COMPUTING SIGHT Filed Oct. 17, 1945 5 Sheets-Sheet 3 -IE- I 97* b 25 gnaw/n40! Lei: HQEu'uwn Patented Dec. 19, 1950 UNITED STATES PATENT OFFICE ocivmo'rn ic SIGHT Lee H. Brown, Glenville, Conn. Application October 17, 1945, Serial No. 622,913 14 Claims. ('01. 33-49) (Granted under the act of March 3, 1883, as

to the gun. The angular correction at the gun or lead, is in all cases that angle subtended at the gun by the target travel during the time of flight of the projectile. This angle is a factor of relative target speed, direction'of target travel relative to the line of fire, and range. For conarnended April 36, 1928; 370 0. G. 757) proportional to the angle of precession of the stain: speed of thetarget across the line of fire the lead angle introduced by the deflection of the sight, assuming constant velocity or" projectile, is inversely proportional to range. Thus the aforesaid angular rate, corrected for range, may be taken as aw measure of the lead, that is, the angle by which the gun should lead the line of sight in the direction of travel of the target relatively to the gun, to effect a hit.

It is an object of the invention to provide a sight of the typedescribed that, except for an adjustment for range, is fully automatic.

A further object'is to'provide a sight in which the'angular rate of the gun is measured as it is moved to keep continuously directed upon the target a line of sight carried by the gun but universally angularly movable with respect thereto.

Another object ist'o provide a lead-computing sight for a flexibly 'mounted gun wherein the constraint of a pair of rate responsive gyroscopes sight for a flexibly mounted gun wherein a pair of rate-responsive gyroscopes precess against the constraint'of a flexible tapered rod to thereby flex the same and provide a curved correcting path along which one of a pair of sights may be translated in accordance with range to thereby provide the correct angle or lead.

A further objectis'to provide a sight wherein the gyro'scopic constraint is varied inversely'with ange so that the computed lead angle is directly a gyroscope and, hence, to the component of target speed across the line of fire.

Another object isto provide a sight, as aforesaid, wherein the angle of precession of the gyroscope is modified in accordance with range so.

that it acts todeflect the line of sight relatively to the gun by a lead angle that is substantially propfiortional to target speed across the line of sigh A still further object is to provide a sight wherein a pair of rate gyroscopes are so mounted as to be responsive to respective mutually normal components of speed of the target across the line of sight, together with mechanism for vec torially combining the aforesaid components and applying the resultant to shift the line of sight relatively to the gun.

Another object is to provide a simplified construction wherein a single restraining means may act upon both 'gyroscopes. A further object is to provide a sight wherein changes in the effects of gravity upon the speed of the projectile, with changes in the angle of gun elevation, are correctly compensated. "A still further object is to provide an accurate andeffective mounting for the sighting mechanism-that will render the same substantially unafiected by recoil of the gun and other shocks and vibration. Other objects and advantages will become apparent as the description proceeds.

- In the drawing: Figure 1 is a perspective view of the preferred form of the invention showing a portion of the gun, the sight casing, its mounting upon the gun, the'sights, and the range adjustment features. v

Figure 2 is a detail perspective view of the two rate responsive gyroscopes and their association with a common sight-deflecting mechanism, Figure 3 is a vertical axial section through the traveling sleeve carrying the front sight and showing the manner in" which the sleeve is mounted and adjusted for range. I

Figure 4 is a section taken upon the line 1-4 of Figure 3 showing the splined connection be tween the sight sleeve and the sight-carrying rod,

.Figure 5 isa perspective view showing the mechanism employed to correct for variation in projectile speed caused by the effect of gravity at different angles of gun elevation,

Figure 6' is' a plan View, partly in section, of a modified form of the inventionwhereinthe constraint applied to the gyroscopes is varied inversely proportional to range and wherein the correcting device of Figure 5 is incorporated,

Figure '7 is a side elevation, partly in section, of the means for compensating for variations in projectile velocity with changes in gun elevation,

Figure 8 is an' elevational view of a portion of a modification wherein the precessions of the respective gyroscopes are accurately applied to the sight-deflecting rod.

Figure 9 is a perspective view of the modification of Figures 6 and '7 showing how a single adjustment adjusts the front sight and gyroscope constraining means in accordance with'range,

Figure 10 is a rear elevation of the construction shown in Figure 9,

Figure 11 is a sectional view taken in a vertical plane indicated by the line I l-H, Figure 10; and

t Figure 12 is a sectional view taken in a plane indicatedby, the line l2--l2, Figure 10.

In the drawing, the numeral I identifies the magazine portion ofa sun which maybe acaliber .50fmachine gun having a flexible mounting and controlled in aiming movement's by a pair of na nies; one of which is shown at 2. A block of frame 3' is fixed to the top of the magazine and; at the right side has a pair of identical links [and 5, pivoted thereto on parallel axes, transversely of the gun bore, as by means of screws 8 and l. A second pair of links, one of which is indicated at 5", are duplicates of 4 and 5 and are similarly pivoted to frame 3- at the left side of the gun; These two pairs of links are pivoted at their upper ends by such as screws. 8 and 9, to the sides of a base or casing [0. This mounting provides for movement of casing. in the normally vertical. plane through the gun bore, while at the same time maintaining the casing fixed angular relation to the gun and" to frame 3'.

Anumber. of superposedor stacked leafTsprings l'll are provided to urge the links to the normal position. shownv in Figure 1-. Alternate springs have one end fixed to link 'by means of a plate l2 riveted thereto.v The remaining springs, which areinterleaved with those secured to link 4', are fixed to link 5 by: means of a plate l3,, riveted thereto The springs may be of. a length such that those secured to link 4, overlap-by a substantial distance, those secured to link 5; In this manner, the springs are flexed whenthe links are pivoted about screws 6 and l by forward and backward movement of casing iii relatively: to frame 3, and act to urge thecasing to the normal position shown inv thefigure. If preferred, all springs may be clampediat one end to link 4, for example, and may have their other ends slidably associated with the other link such as 5. In either. case the springs and mounting may be duplicated at each side of casing l0 to provide a resilient yielding mounting that eifectively protects the parts-carried by casingv l0v against. injury or deleterious influence caused by the recoil of thegun.

Th casing ID has an enlarged aperture in its forward wall M, closed by a flexible element or diaphragm I5. This diaphragm may be'of rubber or" thin sheet metal'and has a central hub portion It apertured to provide a close accuratefit for a rod IT; The diaphragm'm'ay be secured to wall f4" adjacent the periphery of the aperture therein by rivets or screws; Becauseof its close lit in hub portion It, the rod H" is maintained against rotation relatively to'the diaphragm while at thesame time'b'eing free for'universalpivotal movement relatively to casing [0, through a limited range of angles. The rod H has a link it fixed to its forward end to form an operating connection with the forward end of flexible rod [9 whose purpose and function will be subsequently described.

An L-shaped bracket" 2% is fixed to the rear wall of casing IE and carries at its upper end a sight such as peep sight 2i. In addition, rod I9 is rigidly fixed at its rear end, to bracket 20 whereby it tends to return to the normal or undefiected position shown at Figure 1, when a deflecting force i applied to its forward end by angular movement of rod H. The rod i9 is tapered to have decreasing cross sectional areas from itsfixed end outwardly. The decrease in cross sectional area is a function of the distance of each section from the fixed end of the rod. This function, being empirical, is determined experimentally 50 that the deflection from zero position of each point on the rod is that amount necessary to give the correct lead for a target that is at'the corresponding range and is moving at an angular velocity that will cause the gyroscopes to effect that particular deflection of the rod. I have found that the rod which is correct for one angular rate of target, is' approximately correct for all other angularrates for a given ammunition and type of gun.

As shown at Figure l, a flexible strip'extends in the form of a helix about rod iii to form a thread element 22 rotatable on and'a'bout rod [9 as an axle. A pinion 23 is journaled-upon rod is at the end thereof adjacent bracket 20 and one end of helix element 22 is secured to said pinion so that the two rotate as a unit. A second pinion 2G is journaled on a stub shaft, not shown, carried by bracket 26. Rotation of this pinion and, thereby of pinion 23 and element 22, is effected by the turning of a thumbwheel 25journaled in brackets 26 and 27, secured to the side of the gun receiver in position convenient for operation by the thumb or finger of the gunner as he grasps handle 2'. flexible shaft 28 transmits the rotations of thumbwheel 25 to pinion 24. If desired, range indicating means maybe connected for actuation by thumbwheel 25 or pinion 2 1. Such means might comprise, for example, a pointer rotated synchronously with thumbwheel 25 and moving over a scale graduated in range.

From Figures 3 and 4'it willbe noted that rod 59 is sp'lined as at 29 and that a sight-carrying sleeve 30 has an axial bore 3| threaded to receive the convolutions of helix 22 so that, when said helix is rotated, sleeve 30 is translated axially along rod I91 Rotation of-slecve 30 about rod I9 is prevented by a screw- 32 threaded into sleeve 30 and having a reduced end slidably fitting spline 29', A standard 33 is affixed to and rises from sleeve 36 and carries a ring sight 34 at its upper extremity. This sight may have any convenient or desired number of concentric rings, two being shown for the purpose of illustration. Each ring is intended for use with a particular type or size of enemy aircraft and is so dimensioned that when a craft of the type or size for which anyringis intended, is so viewed while proceedingsubstantially along a line from gun to target that the wing tips or other known observable dimension of the target coincide with the opposite ends of any diameter of the ring, the distance of sight 36 from peep sight 2| will be directly proportional to the range of the target; In this manner, the sight maybe quickly and accurately adjusted for range and this is, in fact, the only manual adjustment necessary. Sights 2! and 34, together with the means for efiecting relative translation toward and from each other, constitute a stadia type range finding sight. It is contemplated that-sight 34 may comprise a plurality of concentric rings, one for each type of enemy aircraft expected to be engaged. Or a plurality of detachable and interchangeable sights 34 may be provided, each having a single ring of dimensions corresponding to those of a particular type of enemy craft expected to beengaged.

From Figure 2 it will be noted that the end of rod I! within casing I0 is engaged and cone trolled by a pair of two-degree-of-freedom rateresponsive gyroscopes 35 and 36. Gyroscope 35 has a rotor 31 mounted by a gimbal ring 38 for spinning on a normally horizontal axis 39. Trunnions 40 and 4| on ring 38 are journaled in suitable framework, not shown, so that the axis of said trunnions is substantially parallel with the gun bore. Gyroscope 35 is positioned below rod I! so that the tines on a forked arm 42aflixed to ring 38, embrace rod i1 with'a smooth sliding fit. In this manner, precessional movements of gyro 35 about trunnions 40 and 4|, act to pivot rod l1 horizontally.

Gyroscope 36 includes a rotor 43 mounted for spinning in a gimbal ring 46 about anormally vertical axis 45. Gimbal ring 44 has trunnions 46 and 41 by which it is pivotally mounted about an axis parallel to the axis defined by trunnions 40 and M, and substantially parallel with the gun bore.- A forked arm 48 is afiixed to gimbal 44 and extends substantially horizontally so that its tines embrace rod I! with a smoothsliding fit whereby precession of gyroscope 36 about the axis of trunnions 46 and 41, acts to pivot rod I1 vertically. It will be understood that both gyroscopes and. the parts carried thereby, are balanced about the trunnion axes. The rotors may be spun either electrically or pneumatically, by means well known in the art.

As is well known, the lead between the line of sight to a moving target and the gun bore, laid off in the plane determined by the line of sight to the target and the target path,-is the angle subtended at the gun by a distance, laid oif along said path, equal to the product of the time of flight of the projectile and the average velocity of the target during such time. It is conventionally assumed that the time of flight is directly proportional to range and, under this assumption, the angle of lead is dependent only upon the value of the velocity of the target since the time of flight then decreases in direct proportion to decrease in range. Thus, for a constant speed and heading of a target, the afore said lead will also be constant for all effective ranges of the gun. However, by changing the taper of the flexible rod it is possible to introduce a correction for the decrease in projectile velocity due to air resistance with increases in range. The speed of rotation of the gyroscopes is maintained constant and, provided the gyroscopic constraint is substantially directly. proportional .to the angles of precession, said angles will be substantially proportional to the angular rate of the target as the gun is angularly moved to maintain its line of sight directed thereon. This rate, for the assumed condition of constant target velocity and heading, will increase with decrease in'range. Thusj'in order to maintain the angle stant conditions of target speed and heading, it is necessary to decrease, with decrease in range, the effect upon the line of sight, of a given angle of precession of the gyroscopes about their respective precession axes. Or, stated in a diiier ent manner, it is necessary, for the assumed constant conditions of target movement, that the precession of the gyroscopes be effective to cause substantially the same angular deflection between the gun bore and the line of sight for all ranges. The deflection then varies substantially with target speed plus a small correction, when desired, for decrease in average velocity of the projectile with increase in range. w

In the preferred form of my invention, as shown at Figures 1 and 2, the foregoing correction is effected by the rod l9 and the associated sighting means in a substantially precise and accurate manner. The rod l9 being fixed at one end in bracket 20 affords the principal resilient constraint against which the gyroscopes precess. Thus, for a given angular rate of movement of the line of sight in a horizontal plane, corresponding to a certain horizontal component of target speed across the line of sight at a certain range, the gyroscope 35 will process about its trunnion axis lll-4'l and, through rod ii and link [8, will deflect the forward end of rod 19.

Because of its flexibility and that of element 22, the rod will now assume a curved form in which each point thereon will be deflected from its unstressed or undeflected position by a distance proportional to the correct lead angle for a corresponding range of the target and the same horizontal component of speed across the line of sight. Thus, to introduce the proper lead for all conditions of range and target speed, it is merely necessary to adjust sleeve 30 along rod IS and helix element 22 in accordance with range and to move the gun smoothly to keep the line of sight upon the target.

If desired, a correction may be introduced for the slowing of the projectile due to gravity. This correction is a function of the sine of the angle of quadrant elevation, being a maximum at quadrant elevation. Merely to illustrate the principle upon which the corrector operates, I have shown it at Figure 5, as applied to the preferred form of Figures 1 and 2. In Figure 5,,a spring 54 has one end connected to the adjacent end of rod ll. The other end of the spring is secured to a cord 55 passing over a pulley 55 and supporting a weight or plunger 52 guided for translation in a cylinder 53. In the zero quadrant elevation position of the gun, the cylinder 53 is vertical and the full weight of plunger 52 is effective to restrain rod ii against displacement. At the other extreme, when the gun is elevated to 90, the cylinder is horizontal and the restraint imposed thereby upon rod l? is zero. For intermediate positions, the restraint on rod I? is substantially proportional to the cosine of the angle of elevation. Thus, by the proper selection of weight 52 with relation to the constants of the instrument the variation in speed of the projectile due to the eifect of gravity thereon, may be properly compensated.

In a modified form of the invention shown at Figures 6, 7 and 9 through 12, I apply the constraint to the gyroscopes by a spring connected to the rear end of rod ii. In these figures, the rear wall of casing Hi has an integral sleeve til projecting therethrough and provided with a squared passageway 6| to slidably accommodate of lead constant for all effective rangesQfo'rcori- 2 7 a correspondingly shaped plunger 62 having an 7'. ihtegraltflangefiiiz and a central opening threaded tmreceive a screw 64, At: the outsideof the easing sleevefill is. threaded .toreceive the swiveled coupling member 650i an end of a flexible shaft 51. A counterbore. E is. provided in the outer end of sleeve to; to receive a flange fil secured tosthe. adjacentend or screw 64. The parts are properly proportioned: sothat, when member 65 is turned down as. shown, ample clearance for flange 615 is provided so thatiscrewM. may rotate freely whil'e at the same time being. held against axial displacement. The flange and adjacent endi-ofscrew 642 are provided with a non-circular axial hole adapted to receive. the correspondinglyshaped end of core 880i flexible shaft 5 i. In this way, screw -54. is turned by flexible shaft 5:! and plunger 62 is translated axially along sleeve 69 to thereby vary the tension upon restraining spring 49. The other end of flexible shaft may be connected to pinion 24', Figures 9*to- 12, to be driven thereby in accordance with range, With this construction, rod is, may be substantially rigid and, together with pinions 23 andz hmounted for un-iyersal pivotal movement, asby a gimbal mounting, upon bracket 20.

Thus, referring to Figures 9 through 12, sight bracket 28., having peep sight 2|, carries a gimbal ring '91 pivoted upon a normally vertical axisand in. turn, supporting. a sleeve 9.0 on a normally horizontal axis. The rear end of. rod 19' may be secured in a reduced portion of sleeve 90, as clearly shown at Figure 12. Gear 23' may be journaled in sleeve and provided with a central axial bore through which rod it freely passes. Axial movement of gear 23 may be prevented by a groove 235a, Figure 12, in the hubof the gear, together with a: set screw 2%. Spiral or helical member 22 is rotatably mounted on rod It and attached at one end to gear 23' as in the speciesof Figure 1.

Gear 24 in mesh with gear 23, is journaled in a bracket 92 attached to sleeve 93. Gear 24 is driven by flexible shaft 28 from thumbwheel 25 as in the species of'Figure l and flexible shaft 511, one end of which is shown in Figure 6, has

its other end connected to. be driven by gear 2'4". Thus common means, namely thunibwheel 25, shaft 2%, gear 2 and shaft 5!, are provided to, at one and the same time, adjust the front sight 34 and the tension of spring as, for range.

A bracket indicated generally by the numeral 69, has a flange 5d. Flanges caand "it may be connected by sections of wire ll bent to pass through holes in each flange.

A pulley 1.2 is journaled in bearing standards 13 and I4 extending from flange Til in such a position that cord 15. passing thereover, has one portion extending substantially axially of rod ll. The adjacent end of this cord is connected to. a coil spring 54. The other end of spring 54 is secured to the end of rod ll. Cord 15. passes downwardly through a central opening, l6 in a plug ll. This plug is screw-threaded into the end of a cylinder 13 having flanges 'lil' for securing the same in position. A weight or plunger 80 slidably fits within cylinder 18: as explained in connection with Figure 5, and is secured to one end of cord l5. As the cylinder ES-is vertical when the gun is horizontal the restraint. imposed upon rod [l by weight 525, will be a function of the cosineof the angleoi elevation and will be a maximum for zero. quadrant elevation and zero for 90 elevation. Furthermore, any force exertedby weight allis, by: the construction shown, added to that exerted by spring, 4.9. The conor My! 8 stants are selected: so that, for example, for a given. or fixed, horizontal speed component of the target. normal to the line of sight, the angle of precessionof the gyroscope 35 will be substom tiazlly constant irrespective of range and the gun will be? given an angular lead as the. line of sight i'sz-maintained upon the target,,such that the lead will subtend a. linear distance along the path of thetargetequal to the product of average target speedand timeof flight of projectile.

The. operation of this form of the invention will nowbe clear. .After the enemy craft to be engaged, is identified, thumbwheel 25 is rotated until the wing spread, or other identifiable dimension; of thecrafit, is. subtended by a diameter of. the: appropriate: ring of sight 34'. This adjustment operates to position sight 34 in accordance with. range. and to. tension spring, 49 inversely in proportion to range, thatis, the shorter the range, the greater the tension in. springv 49. With the gyroscope's. spinning, as.- the gun is moved to maintain the. line of sight upon the target, the component. of angular movement in the plane through the. lineof sight normalto the gun trunnion axis, affects. gyroscope 36 and causes it to precessabout trunnions. 48 and 41. While, for any fixed target speedv component. across the line of sight, the angular rate of the gun will increase with. decreasein rangaat the. sametimethe tensiorr of spring 49 is also increased as the range decreases. As a result, the angle through which the gyroscope. precesses will be substantially directly. proportional to. the. target speed component across the lineot sightv lying. in the plane mentioned and the line. of sight is so moved angularly relatively to the gun. as to cause the gun to. lead the. target. by the amount necessary to cause. the projectile to strike the target at the. future or. predicted: position of the latter.

Likewise, the. component of angular movement of: the gunin the plane through the. line of sight parallelto the. trunnionaxis, will apply a precessing torquetogyroscope 35: through the trunnions 40 and 4| and cause. said gyroscope to preccss aboutthelaxisiofasaid. trunnions through anangle that,,.due to: the. variation in tension in spring 49. inversely with range, will be substantially direetly proportional to the. component speed of the target across. the line. of sight and in the plane: mentioned. Each gyroscope. acts through its-forked arm. and. 4.8, respectively, to displace rod 1:1: and hence. element. 22 and the line of sight, through an angle. lying substantially in the respective. planes. mentioned. As a result, the combined. angular deflection is correctly applied. so. that,.as= the. gun is moved to maintain the line of sight upon the target, the gun is caused to lead the. target. by the. proper amount necessary to effect hits. thereon. At the same time the restraint upon rod I]. is varied by weight in proportion to the sine of the angle of gun elevation to efiectively compensate for changes inthevelocity of the projectile caused by gravity. In-every situation, the. forcev acting upon rod llv tending. to restore it. and the gyroscopes to neutral or zero position will. be the combined stress in spring 48. plus any tension in cord 15, plus any. moment. applied. to rod. H; by diaphragm l5. It willbe noticed that. the species of Figures 1 and 2, while simple and. inexpensive to construct is not strictly accurate. For example, suppose that gyroscopefi. has. precessed through. a substantialv angle so that. fork 42 has moved rod ll along the slot in fork 48. Under such conditions,;it:is-clear-that the angular degree of movement of rod ll by any given angle of precession of gyroscope 35', will be dependent upon the position to which precession of gyroscope 35 has moved said rod along arm 48. This holds true for both gyroscopes.

, To obviate the error discussed in the preceding paragraph, the modification shown at Figure 8 may be used wherein the gyroscope 36 has a pinion Bl fixed to one trunnion thereof, such as 45'. A T slide 82. has slots 83 and 8 in its head portionthrough which pass rollers or pins 85 carried by any suitable portion of the frame of the instrument to thereby mount slide 82 for vertical translation, as viewed in Figure 8. The edge of the head portion of slide 82 has a rack 86 formed therein and with which pinion 8| meshes. The shaft or shank of slide 82 has a slot Sl therein of a width to receive rod I1 with a smooth fit. Thus, as gyroscope 36 precesses, it causes rotation of pinion 8| and corresponding translation of slide 82. Obviously the angular movement of rod H is substantially independent of its position along slot 81. The mounting of horizontal slide 88 and its connection with gyroscope 35 is identical with that just described and operates in the same manner to translate slide 88 horizontally by and in proportion to the angle of precession of gyroscope 31'. In all cases, each gyroscope is balanced and in neutral equilibrium about its axis of precession so that in the event of pure translation of the gun, neither gyroscope has any tendency to angular movement about the axes defined by trunnions 404l and 46-41.

The use of the invention will now be clear. When an enemy aircraft is sighted and identified as one for which the particular sight 34 is de signed, the gunner grasps the handles one of which is shown at 2, and, sighting with his eye closely adjacent sight 2|, observes the target and rotates thumbwheel 25 to thus axially translate sleeve 38 and sight! until a diameter of the ring Z-M subtends the wing spread or other equal observable dimension of the target. Thumbwheel 25 may be rotated to continuously maintain the range adjustment during the engagement. As the gun is moved angularly in the manner necessary to keep the line of sight upon the target, the component of angular movement in the vertical planeacross the line of sight applies a torque to gyroscope 36 changing the direction of the spin axis. In accordance with the well known law of precession, the gyroscope then precesses in the direction necessary to place its spin axis in alignment with the axis of the applied. torque and so that the directions of rotation are the same. In the connections shown upon Figure 2, the directions of rotation of the gyroscopes are as indicated by the arrows. These directions are such as to always cause the line of sight to lag behind the gun in the direction of target travel whereby, when the gun and sight are advanced as a unit to maintain the line of sight directed upon the target, the gun will lead the target by the correct distance. Under all conditions, the weight 39 acts to apply a restraining force to rod ll that varies as the sine of the angle of gun elevation. This force acts to reduce the precession angle for small angles of gun elevation. Since the reduction in bullet velocity is greater the greater the angle of gun elevation, the net result is to slightly increase the lead angle forlarge angles of gun elevation for the same conditions of target speed and heading. This is necessary because of the greater time of 10 flight with lower average velocity of theprojectile,

The modification of Figure Smay be usedin connection with Figure 1 or Figure 6. This modification gives somewhat more accurate results but is, at the same time, more complicated to construct.

While I have shown a preferred form of the invention, together with several modifications, it will be obvious to those skilled in the art that numerous changes, alterations and substitutions are possible without altering the basic principles upon which the instrument operates. Conse: quently, I do not wish to be limited to the precise details of construction shown but to reserve .all such modifications and substitutions of equiv; alents as fall within the scope of the subjoine'd claims. I

Havingnow fully disclosed the invention, what I claim and desire to secure by Letters Patent is:

1. In a lead-computing. sight, a base adapted for mounting upon a gun for movement in .train and elevation therewith, rod means having one end mounted at a first point on said base, a fixed sight carried by said base adjacent said first point, a second sight mounted for translation on and along said rod means to vary the separation of said sights in proportion to the range of a target, means operable to so translate said second sight, rate responsive gyroscopio means carried by said base and operable to precess in response to angular movement of said gun. in any plane, and connections between said gyroscopic means and said rod means and effective to angularly displace said second sight in said planerelatively to said gun.

2. In a lead computing sight, a base adapted to be attached to and move angularly with a flex.- ibly mounted, gun, a flexible rod-like element having one end rigidly carried by said base at a first point, a first sight carried by said base adv jaoent said first point, a second sight mounted for translation only on and along said rodlike element, means to so translate said second sight to vary the distance between said sights inac cordance withrange of a target, and gyroscopic means carried by said base and connected toflex the other end of saidrod element in proportion to the rate of angular movement of said gun as said gun is angularly moved to maintain thelin of sight determined by said sights directed upon a target. 7

3. A lead computing sight comprising a base adapted to be secured to a gun for angular movement therewith in train and elevation, flexible rod means having one end rigidly fixed to said base at a first point and extending generally parallel with the bore of said gun, a first sight car ried by said base adjacent said first point, a second sight mounted for translation on and along said rod means, manually operable means to so translate said secondsight to vary the separation of said sights proportional to the range of a target, and gyroscopic means carried by said base and connected with the other end of said-rod means to deflect the same proportional to the instantaneous rate of angular movement of said gun as the line of sight determined by said sights is maintained directed upon a target.

4. A lead computing sight for a gun comprising a base adapted to be mounted for movement with said gun in train and elevation, a rod universally pivoted at a first point upon said base, a first sight carried bysaid base closely adjacent said first point, a second stadia type range-finding sight carried for translation only by and along ate-4,225

.saidirod, manually operable means for so transilating'said second sight; a gyroscope mounted for precession on said base in response to angular movement of said gun and base about a predetermined axis, a connection angularly moving said rod relatively to said base about an axis through said first point parallel to said predetermined axis in response to said precession, means operated by said manually operable means to vary the, angular: movement of said rod in accordance with rang as determined by said second sight, and means resiliently constraining said gyroscope.

.5. Ina sight, a base adapted to be mounted upon a gun, a rotatable helix element universali'y pivoted at a first'point carried by said base, a sleeve mounted for translation by and along said helix element as the latter is rotated, a range finder sight carried by said sleeve, 9, second sight fixed on said base at said first point, gyroscopic means on said base and adapted to precess upon angular movement of said base and gun about a predetermined axis, resilient mean connected to constrain said precession, said resilient means being. adjustable to vary said constraint, a connection adjusting said constraining means with and in proportion to the rotation of said helix ele-- ment, and a connection for pivoting said helix element by and in response to precession of gyroscopi-c means.

6'. In a sight, a base adapted to be connected with a flexible type gun "for angular movement therewith about a predetermined axis, a sleeve, a range finder sight mounted upon said sleeve, a second sight carried by said base and fixed thereto, said'sights cooperatin to determine a line of sight to a target, means mounting said range findersig'ht for universal pivotal movement about said second sight as a center, and for translation toward and from said second sight along said line of sight, at gyroscope mounted on said base for precession in response to said angular movement, constraining means connected with said gyroscope and adjustable to vary the constraining "force imposed thereby, manually operable means for adjusting said cons-trainin means and simultaneously translating said range finder sight, and means responsiveto precession of said gyroscope to move aid' sleeve relatively to the gun to correspondingly deflect the line of sight determined by said sights.

7. In a sight, a base adapted to be mounted upon a flexible type gun, a rotatable helix element universally pivoted at a first point carried by" said base, a sleeve mounted for translation only by and along said helix element as the latter is rotated, a range finder sight carried by said sleeve, a second sight fixed on said base at said first point for cooperation with said range finder sight to determine a line of sight, gyroscopic means on said base adapted to process upon angular movement of said base and gun about a predetermined axis, resilient means to constrain said movement, said resilient means being adjust-- able to vary saidconstraint, a connection adjusting said constraining means by and in proportion tothe rotation of said helix element, and a connection for pivoting said helix element by and in response to precession of said gyroscopic means to an'gularly deflect said line of sight relatively :said gun in train and elevation, a rod, resilient diaphragm means mounting said rod for universal pivoted movement on and with respect to said base, first and second rate responsive gyroscopes on said base, each reponsive to angular movement of said gun about respective first and second mutually normal axes, means connecting each gyroscope to said rod to pivot said rod about axes parallel to said first and second axes, respectively, in opposition to the constraint of said diaphragm means, means carried by said base and determining a line of sight for aiming said gun, and a connection between said last-named means and said rod and effective to deflect said line of sight means relatively to said gun.

9. In a lead computing sight for a gun mounted for angular movement about train and elevation axes, a base carried by said gun for angular movement therewith, first and second sights coacting to determine a line of sight for said gun, means mounting said sights upon said base so that the line of sight determined thereby is universally pivotally 'inoveable with respect to said gun, and including means mounting one sight for translation toward and from the other, rate responsive gyroscopic means carried by said base, a connection between said gyroscopic means and said sight mounting means to adjust said line of sight relatively to said gun about an axis parallel to the instantaneous axis of angular movement of said gun as the latter is moved to maintain said line of sight upon a target, and manually operable means connected to effect relative translation of said sights toward and from each other to determine the range of a target and to simultaneously vary the ratio of the angle of precession of the gyroscope to the resulting angle of movement of the line of sight relatively to the gun.

1:). A lead c inputing sight for a flexibly mounted gun comprising a casing, shock absorbing means adapted to mount said upon said gun for angular movement therewith, a diaphragm carried by said casing, a rod mounted for universal angular movement by said diaphragm, first and second gyroscopes mounted in said casing with their spin axes normally mutually perpendicular and their precession axes generally parallel to said rod, connections angularly moving said rod in respective mutually perpendicular planes by and in response to the movement of said gyroscopes about their axes of pre cession, a spring connected at one end to an end of said rod, adjustable means connected with the other end of said spring and movable to vary the tension applied thereby to said rod, a sight device. means mounting said sight device on said casing so that line of sight determined thereby is universally angularly adjustable relatively to said casing, said device being adjustable in accordance With the range of a target, a connection for adjusting said device to move the line of sight relatively to the casing in response to angular movement of said rod, and a common manually operable means to adjust said adjustable means and said line of sight device for range.

11. In a lead-computing sight, a flexible, tapered rod having its larger end fixedly mounted at one point upon a flexibly mounted gun, a first sight adjacent said one point, a second sight mounted for translation only on and along said rod in accordance with range of a moving target, and means deflecting the smaller end of said rod in proportion to the angular rate of movement of the line of sight determined by said sights as said line of sight is maintained upon said target.

12. A computing sight adapted for mounting upon a gun for angular movement therewith about train and elevation axes, said sight comprising a base, a first gyroscope mounted on said base to precess in response to elevation of said gun, a second gyroscope mounted on said base to precess in response to training of said gun, a single coil spring constraining both said gyroscopes against precession, a range finding line of sight device for said gun, means mounting said line of sight device on said base so that the line of sight determined thereby is universally angularly adjustable relatively to the gun, said line of sight device being adjustable in accordance with the,

range of a target, a single means connected to adjust said line of sight device for range and simultaneously to vary the tension of said spring and the constraint imposed thereby upon said gyroscopes, and means responsive to precession of said gyroscopes in response to angular movement of said gun in tracking a target, to angularly 14 component to said spring in accordance with the cosine of the angle of gun elevation, said lastnamed means comprising a weight, means on said base guiding said weight for movement in a straight path, said path being substantially vertical when said gun is at zero elevation, and a connection between said weight and spring.

LEO H. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,936,442 Willard Nov. 21, 1933 2,012,960 Coupland Sept. 3, 1935 2,066,499 Watson Jan. 5, 1937 2,405,068 Tear et a1. July 30, 1946 2,407,191 Tear et a1. Sept. 3, 1946 2,441,147 Haubroe May 11, 1948 2,464,195 Burley et al Mar. 8, 1949 2,467,831 Johnson Apr. 19, 1949 FOREIGN PATENTS Number Country Date 404,719 Great Britain July 27, 1933 870,388 France Dec. 12, 1941 

